Auto-generate markdown command docs (#4451)

* Finish updating

* a couple improvements

* Update renames

* cleanup examples

docs/commands/for.md

@@ -1,34 +1,36 @@
-# for
-Run a block on each row of the table.
+---
+title: for
+layout: command
+version: 0.59.0
+---
 
-## Usage
-```shell
-> for <var> <in> <value> <block> {flags} 
- ```
+Loop over a range
+
+## Signature
+
+```> for (var_name) (range) (block) --numbered```
 
 ## Parameters
-* `<var>` the name of the variable
-* `<in>` the word 'in'
-* `<value>` the value we want to iterate
-* `<block>` the block to run on each item
 
-## Flags
-* -h, --help: Display this help message
-* -n, --numbered: returned a numbered item ($it.index and $it.item)
+ -  `var_name`: name of the looping variable
+ -  `range`: range of the loop
+ -  `block`: the block to run
+ -  `--numbered`: returned a numbered item ($it.index and $it.item)
 
 ## Examples
-  Echo the square of each integer
+
+Echo the square of each integer
 ```shell
 > for x in [1 2 3] { $x * $x }
- ```
+```
 
-  Work with elements of a range
+Work with elements of a range
 ```shell
 > for $x in 1..3 { $x }
- ```
+```
 
-  Number each item and echo a message
+Number each item and echo a message
 ```shell
 > for $it in ['bob' 'fred'] --numbered { $"($it.index) is ($it.item)" }
- ```
+```